The invention relates to a sintered compound material of silver, stannic oxide, bismuth oxide and copper oxide for use in electrical contacts and to a method for its production.
For many applications, AgCdO has served very well for the manufacture of electrical contact elements. Because it contaminates the environment, however, CdO has been classified as a toxic material. Attempts have therefore been made to replace CdO by another metal oxide. It has turned out that stannic oxide (SnO.sub.2) is a suitable substitute for cadmium oxide (CdO), although AgSnO.sub.2 contact materials still do not have optimum values in all the operationally important properties. For instance, AgSnO.sub.2 contact materials exhibit a more firmly adhering oxide layer than do AgCdO contact materials.
The European Pat. No. 0,024,349 discloses a material for electrical contacts consisting of silver, stannic oxide and another metal oxide. This known contact material contains stannic oxide and tungsten oxide, in a certain specified composition, as well as silver.